In general, a heat-cooker such as a cavity assembly of frying pans, saucepans, woks, gas oven ranges, or microwave ranges to which high-temperature heat is transmitted is manufactured using an aluminum or stainless steel material. Also, the surface treatment is performed on the heat-cooker using various methods to improve the physico-chemical properties such as durability, heat resistance, and the like of such a material. For an iron and steel material, an enamel coating is mainly performed, but it typically does not have a non-stick function and thus food sticks to a cooking surface of the heat-cooker during cooking, which leads to an great increase in dissatisfaction of consumers. Therefore, the improvement of the heat-cooker is required urgently.
As a solution to address and solve the problems involved in the heat-cooker having a body made of an iron and steel material, Korean Utility Model Registration No. 202236 discloses an enameled heat-cooker including a polytetrafluoroethylene (PTFE) coating layer in which an enamel layer 30 is formed on the entire main surface of a body 10, and a polytetrafluoroethylene (PTFE) coating layer 40 is formed on one surface of the body as shown in FIG. 1. In addition, Korean Patent Registration No. 394045 discloses a heat-cooker in which a coating treatment is performed on the inner and outer surfaces of a body 10 made of an iron or aluminum material, an enamel layer 30 is formed on the outer surface of the body, followed by hot drying, a fine corrugated pattern is formed on the entire inner surface of the body 10 and a thermal spray coating is performed thereon, and a polytetrafluoroethylene (PTFE) layer 40 is coated in a multiple stack manner on the inner surface of the body 10, followed by hot drying as shown in FIG. 2.
However, for the above heat-cooker, as a non-stick ceramic coating layer made of a polytetrafluoroethylene (PTFE) resin is formed on the body of the heat-cooker, a surfactant called PFOA (Perfluorooctanioc acid) as a catalyst recently used in the preparation process of a fluorine resin such as polytetrafluoroethylene (PTFE) may threaten the health of pregnant women or young girls at childbearing ages according to an internal report of the U.S. Environmental Protection Agency (EPA). In addition, the conventional heat-cooker entails problems in that even if polytetrafluoroethylene (PTFE) as a coating material is heated up to 260° C., a polytetrafluoroethylene (PTFE) coating layer is decomposed, and thus food may adhere to the cooking surface of the heat-cooker when it is used for a long period of time or is used at high temperature.
Meanwhile, the present inventor has developed various techniques for the surface treatment of a body of the heat-cooker made of an iron and steel material in view of the above-mentioned problems, and Korean Patent Registration No. 512599 disclosing an anion-radiating and far infrared ray-emitting inorganic ceramic coating composition has been registered, and Korean Patent Registration No. 765382 disclosing a structure of coating layer for heat-cooker has been registered, and Korean Patent Registration No. 871877 disclosing a ceramic coating metal heat-cooker and a manufacturing method thereof, which is an improvement of the above patents, has been registered.
Therefore, the present inventor has manufactured a non-stick enameled heat-cooker in which an enamel layer is coated on the outer surfaces of a body made of an iron and steel material, and then a non-stick ceramic coating layer is formed on the enamel layer by employing the ceramic coating technique applied to the above patents, thus completing the present invention.